Astrology is bogus. So is a bolt that is obviously about to break.
So is someone who makes blatantly false claims to have solved a
scientific problem. (This word seems to have some, but not all, of
the connotations of random -- mostly the negative ones.)

It is claimed that `bogus' was originally used in the hackish
sense at Princeton in the late 1960s. It was spread to CMU and
Yale by Michael Shamos, a migratory Princeton alumnus. A glossary
of bogus words was compiled at Yale when the word was first
popularized there about 1975-76. These coinages spread into
hackerdom from CMU and MIT. Most of them remained wordplay
objects rather than actual vocabulary items or live metaphors.
Examples: `amboguous' (having multiple bogus interpretations);
`bogotissimo' (in a gloriously bogus manner); `bogotophile'
(one who is pathologically fascinated by the bogus);
`paleobogology' (the study of primeval bogosity).

By the early 1980s `bogus' was also current in something like
hacker usage sense in West Coast teen slang, and it had gone
mainstream by 1985. A correspondent from Cambridge reports, by
contrast, that these uses of `bogus' grate on British nerves; in
Britain the word means, rather specifically, `counterfeit', as in
"a bogus 10-pound note". According to Merriam-Webster, the word
dates back to 1825 and originally referred to a counterfeiting machine.